Liquid level gauge



Feb 6, 1945- A. J. Rosl-:NBERGER 2,368,616 v LIQUID LEVEL GAUGE Filed Aug. 5, 1943 @y la/inv M 'Qd Attorneys Patented Feb. 6, 1 945`V` UNITED STATES 2,368,616 ploum LEVEL Gauss Albert J. Rosenberger, Chicago, Ill., Vassignor to Republic Flow Meters Company, Ghicago, lill.,

a corporation ci Illinois Application August 5, 1943, Serial No. 497,421

vide a liquid level gauge which indicates the weight of liquid in the tank or container. This construction automatically compensates for 'variations in density due to temperature changes.

A further object of the invention is to provide a liquid level gauge which is not affected by changes in pressure in the tank or container.

-Astill further object of the invention is toY provide a liquid level gauge in which variations in pressure adjacent the tank and adjacent the indicator are compensated.

The above and otherobjects and advantages of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in whichvigure 1 is a diagrammatic section illustrating an installation of a gauge embodying the invention in a tank;`

Figure 2 is an enlarged section of the gauge mechanism; and

Figure 3 is a partial section similar to Figure 2 of a pressure operated mechanism.

The gauge of the present invention is adapted to be enclosed in a tube IIJ which is mounted vertically in a tank or container II containing liquid, as shown. The gauge mechanism I is connected to an indicator I2 which may bei mounted at any desired point remote from the vtank and a pipe I3 leads from a -point adjacent the indicator. into the gauge mechanism to compensate for variations in pressure at the tank and the indicator location as will be explained hereinafter. The gauge mechanism may b e operated by Aiuid under pressure or by vacuum conducted thereto bya pipe I4 from any suitable source;

As bestseen in Figure 2, the pipe ID is formed with openings I5 adjacent its lower end and openings -IS adjacent its upper end communicating with the tank adjacentI the'bottom and top thereof respectively. A flexible diaphragm unit shown as a bellows I1 is mounted in the lower end ofthe tube and is sealed against the tom thereof so that its exterior will be exposed to the pressure in the bottom of the tank II. A similar bellows IB which is matched with the bellows I'I is mounted in an inverted position in the upper end of the tube and has its edge sealed against a flange I9 at the top of the tube. The two bellows are mechanically connected by a pipe 2l extending vertically through the tube and which .establishes :duid communication between the interiors of the bellows vto equalize the pres- .sure therein.

The downward force exerted by the bellows is balanced by a force producing mechanism controlled by movement of the bellows. This mechanisml as shown comprises a flexible diaphragm 22 above the upper bellows connected to the pipe 2I to move therewith and open on its lower side lto the interior of the bellows. The pipe I3 communicates with the space below the diaphragm 22 as shown.

The upper side of the diaphragm is enclosed by a cover 23 and the pressure therein is regulated by movement of the diaphragm and bellows.A For this purpose an atmospheric vent covered by filtering material or the like 24 communicatesv with a nozzle 25 inside the cover 23. 'Ihe nozzle 25 is controlled by a iiap valve 26 pivoted at one end on the mounting for the diaphragm and connected intermediate its ends to a yoke 21 fastened to the upper side of the diaphragm 22. The space within the cover communicates through a restricted orifice 28 with the pipe Ill-which is connected to a source of vacuum. The space in the cover 23 is also connected through a pipe 29 with the indicator I2 so that the indicator will be operated in accordance with the degree of vacuum above the diaphragm 22.

When the 'gauge mechanism is installed in a tank,VV the .lower bellows I.'I will be subjected non lits exterior to the pressure within the tank in:-

cluding any static pressure above' the liquid plus the weight or the liquid column above the bellows. The bellows I8 at the tcp ofthe tank will be subjected only to. the static pressure above the liquid sothat the net effect. will be a downward force proportional to the weight of the columnV of liquidl in the tank. This downward force' isbaIanced by the differential pressure across the diaphragm 22, the degree of vacuum` required to rebalance the downward force being transmitted to the indicator I2 through the pipe 29 so that the indicator will indicate the weight of the column of liquid in the tank. In the betevent that there is any difference pressu between .the space surrounding the indicatorand the atmospheric pressure around the tank, as for example, in aircraft with a, super charged cabinet the pressure diierence will be compensated 6 bythe pipe I3 so that the indicator will at "all times indicate accurately the'weight of the coll umn of liquid in the tank. l

As the liquid level drops thefdownward -force l exerted by the bellows will decrease and the dia- 10 phragm 22 will'tend torlse to move the fiapper 26 away from the orifice 25. This will admit more air to the space above the diaphragm 22 reducing the vacuum therein until the degree of .vacuum is just sumcient to'balancethe down- 15 l ward .force exerted by the bellows; Upon an increase in liquid level the downward force of the bellows will increase, restricting the orice v so that the vacuum above the diaphragm 22 lwill increase proportionately. 20

To prevent erratic operation of the gauge due to operation of liquid inthe tank or the like, the openings-i5 and l'may be restricted to have a damping eilect. This will slightly delay equalizing. of pressures on the interiorlof thetube Ill. 25

and in the tank and will cause the gauge1 to operate somewhat more slowly without, however,

I aii'ecting its accuracy. Ii the tank is operated under increased pressure to assist vin forcing fuel therefrom, the pressure will operate to-the same 30 sure, the compensating bellows i8 may be omit- 35 ted and the remainderoi thel apparatus will function in the same manner as described above.

Figure 3 illustrates a construction similar to lthat shown in Figure 2 and parts therein identi- -cal with corresponding parts inFigure '2 have 40 nectin-g the space around t lbeen marked with the same reference numerals. 'I'he construction oi Figure -3 is adapted to be'operated by iiuid under positive pressure which is supplied through a pipe 3i. The pipe 3| communicates. through an oriiice -32 with the space *45 below the diaphragm 22 which is open to the interior of the bellows I8 and with a nozzle or orice 133 extending into the` space' beneath the cover plate 23 above the diaphragm 22. The o riflee sa is controlled by the' valve lever 2s m vthe' 5 same manner as the oriilce 2B of Figure 2.

The space below the diaphragmvv 22 is connect-` ed by a pipe 34 with a pressure gauge'- simllar e to the -gauge I2 which may be calibrated. to indicate ln terms Aor the welsht'ol llquld ln the tank 5 and the space around thegauge is connected through la pipe 35 to the space beneaththe cover l plate 23 to compensate for any diil'erences in atv mospheric pressure.

e In operation, a downward forcev on'the bel- 6o lows and diaphragm caused-by the 'weishtroi'V the. liquid column tends to move the valve 28 against the orilice .Il toincrease the-pressure below the diaphragm 22.', It will benoted that the pressure increase acting qn bellows: I8 will 0 5- be compensated by an identical increase acting on thelower bellows I1 so that the net result of the pressure increase is an upwardl force on the diaphragm 22. The pressure will increase to a` point suilici'ent to return the valve 26 to its neu- 70 ntral position and will be transmitted through the pipe 34 to the gauge to. indicate the Vweight of liquid in thetank. The. upper side of the diaphragm 22 will always be at thesame pressure as that around the gauge due to the connection through pipe as so' that the gauge will rindicate accurately' the weight ofthe liquid column in the tank.

While two embodiments of the invention have been shqwn and described, it will be understood that these areillustrative only and are not to be taken as a denition of the scope of the invention, reference being had for this purpose to the appended claims. v

' pipe connecting the movable ends of the bellows Ito establish iluid communication between the interiors thereof, a flexible diaphragm above the second bellows and connected to the be1lowsa valve controlled by movement of the bellows and diaphragm to regulate the :pressure above the diaphragm, and an indicator responsive to the pressure above the diaphragm.

l 2. A liquid level gauge 'comprising a tube adapted to project vertically into a liquid tank l and communicating with the tank adjacent its upper and lower ends, a exible bellows in the tube sealed against the bottom of' the tube, a second flexible bellows adjacent the top of the tube sealed' around the periphery of the tube,

a pipe connecting thcmovable ends of the bellows to establish-fluid communication between 'the interiors thereof, a ilexible diaphragm above the secondi bellows and connected to the bellows,

a valve controlled by movement of the bellows and diaphragm to regulate the pressure above the diaphragm, an indicator responsive to the pressure above the diaphragm, anda conduitconhe indicator to the interiors of thebello'ws.

3.v In a liquid level gauge for measuring the liquid level'in a tank, a. pair of vertically Aspaced lhollowbodies each havingan end lwall movaible under pressure, one side of the end walls being adapted to be exposed to the pressures at vertically spaced points in the tank, means connecting said end walls for movement together, and force producing mechanism connected tothev elim walls to move with the, end walls, means connected, to ,the Iforce producing mechanism to sup-- ply operating energy thereto, and control means' connected to the force producing mechan'ismland the end walls to be moved thereby to control the supply of operating energy to the -force producing mechanism tocontrol the force produced by." the force producing `mechanism so that it .will

balance the difference in pressure on the hollow bodies. 4. In a liquid llevel 'gaugefor measuring the liquid level in a tank, a pairof vertically spaced,

Ihollow bodies each havingvan end |wall mov-,v able under pressure, one side of the end 'walls being adapted to' be', exposed to the pressures at vertically spaced points in the tank, means .con-

necting said end walls for movement together,

means controlled by movementof the end walls to produce a regulated iluid pressure, and means responsive to the regulated`iiuid pressure connected to the end wallsto balancefthedierence invp'ressure thereon. v

5. In a liquid level gauge for measuring the liquid levelin a tank, a pair of vertically spaced hollow bodies each having an end wall movable under pressure. one side pf the end walls being adapted to be exposed 4to the pressures ai;l vertically spaced points in the tank, means connecting said end walls for movement together, means controlled by movement of the end walls to producea regulated iluid pressure, meansresponsive to the regulated fluid pressure connected to the'end walls to fbalance the dierence in pressure thereon, an indicator connected to the controlled means to be operated by the regulated pressure, and means connecting the space adiacent the indicator to the other sides of the end walls.

6. In a liquid level gauge for measuring the liquid level in a tank, a pair of vertically spaced hollow bodies each having an end wall movable in response to pressure in opposite directions, the exteriors of said hollow bodies being adapted to be exposed .tothe pressures at vertically spaced points in the tank, means connecting the end walls for movement together' and connecting the interiors oi' the hollow bodiesto equalize the pressures therein, and force producing mechanism connected to the end walls to move with the end walls, means connected to the force. producing mechanism to supply operating energy thereto, l

and control means connected to the force producing'mechanism and the-end walls to be moved thereby vto control the supply of'operating energy to the force producing mechanism to con\..

trol the force produced by the force producing mechanism so that it will balance thediil'erence in pressure on the hollow bodies.

7. In a liquid level -gauge for measuring the I liquid level in a tank, a pair of.;vertically spaced hollow bodies each having an end wal1 movable in response to pressure in opposite directions, the exteriors of saidvhollow bodies being adapted to be exposed to the pressures at vertically spaced points in the tank, meansconnecting the end walls for movementI together and connecting the interiors of the hollow bodies to equalize the pressures therein, means controlled by movement of the end walls to produce a regulated fluid pressure, yand-means responsive to the regulated pressure connected to the end walls -to balance the difference in pressure thereon.

9. A liquid level gauge comprising a pair of vertically spaced hollow bodies having end walls movable in response to the pressure at vertically 'spaced points in a liquid tank, means connecting the end walls for movement together and to equalize the pressure inside the hollow bodies, a ilexible diaphragm connected to the end walls and.

exposed on its lower side to the pressure on the inside of; the hollow bodies, a control valve operated by movement of the end walls to produce a variable degree -ot vacuum `slbove'the diaphrm, and an indicator responsive to the va'cuum above the diaphragm.

l0. A liquid level gauge comprising a pair of vertically spaced hollow 'bodies having end walls movable in response to the pressure -at vertical- 1y. spaced points in a liquid tank, means connecting the end walls for movement together and -to equalize the pressure inside the hollow bodies.

Aliquid level in a tank, a hollow body adapted to be mounted in the tank adjacent the bottom thereof and having an end wall movable in response to the pressure thereon, a force producing mechanism connected to the end 'wall to move therewith, and means controlled bymovement of the end wall and the force producing mechanism to control the force exerted by the force producing mechanism so that it will balance the pressure on the end wall.

12. In a liquid level gauge for measuring the liquid level in a tank, a hollow body adapted to 'be mounted 1n the tank adjacent the bottom thereof and having an end wall movable in vre- 8. In a liquid level gauge for measuring the liquid ieveiin a tank. a pair of vertically spaced hollow bodies each having an end wail movable in response to pressure in opposite directions, the exteriors oi' said hollow bodies beingl adapted to be exposed to the-pressures at vertically spaced points in the tank, means connecting the end walls for movement together and ,connecting the 'interiors o1.' the hollow bodies to equalize the pressures therein, means controlled by movement of the end walls to'lproduce a regulated fluid pressure, means responsive tothe regulated pressure connected lto the enddvalls tobalan'ce the difference in pressure thereon, an indicator connected to the'controlled means'to -be operated by the regulated pressure, and meansconnecting the space adjacent the indicator to theinterior of the hollow bodies.

sponse to the pressure thereon, means connectingthe interior of the hollow body to a space exterior to tank, fluid pressure responsive means connected to the end wall for movement therewith, and means controlled by movement of the end wall and fluid pressure responsive means to producev a regulatedpressure to which the :nuid .pressure responsive means is responsive so that it rwill balance'the pressure on the end wall. 13. In a liquid level 'gauge for measuring the liquid level in a tank, a hollow body adapted to be mounted in the tanlLadjacent the bottom thereof'and having an end wall movable in'response to the pressure thereon, a diaphragm con- Y nected-to the endwall for movement therewith and`to equalize the pressures onbne side of the 'diaphragm and in the hollow body, and valve means controlled by movement of the end wall and the diaphragm tmoontrol the pressure on the other sideo! the diaphragm. 

